Control of product selectivity for a model with mutating autocatalysis

The variation of the selectivity, defined as the yield of one reaction prod uct divided by the total product yield, with the residence time in a model scheme based on "mutating autocatalysis" is considered. Operating condition s spanning several types of bifurcation are investigated and the selectivit y observed from time-dependent integrations compared to those appropriate t o steady-state operation, In one case, complex periodic solutions may devel op through a period-doubling bifurcation sequence, leading to chaotic state s. The simple proportional feedback method is used to compare the selectivi ty of different stabilised periodic orbit under these conditions. It is fou nd that these different states all have similar selectivities to that obser ved in the autonomous chaotic state, but that a significant change in selec tivity can be achieved at the same operating conditions by targeting a coex isting stable period-1 orbit lying on a separate branch of solutions. (C) 2 001 Elsevier Science Ltd. All rights reserved.